(a) Technical Field
The present disclosure relates to a fuel system for a bi-fuel vehicle and a method of charging a bi-fuel vehicle with liquefied petroleum gas (LPG) fuel using the same, more particularly, to a fuel system that decreases pressure in an LPG tank for a bi-fuel vehicle.
(b) Description of the Related Art
In general, an engine for a vehicle combusts fuel to reciprocally move pistons in order to obtain power required to drive the vehicle, and the reciprocating motion of the pistons is converted into rotational motion, thereby driving the vehicle.
As described above, the combustion of fuel is an essential element for driving the vehicle.
Recently, vehicles that use electricity or hydrogen as a power source have been produced, but these vehicles have not yet been widely used, and gasoline, gas or the like is typically used as fuel of the vehicle.
In this regard, a vehicle that stores both gasoline fuel and gas fuel so that the fuel may be selected and supplied to the vehicle in accordance with a driver's intention, is referred to as a bi-fuel vehicle (also known as a dual fuel vehicle). For example, one internal combustion fuel can be gasoline (or diesel), and another internal combustion fuel can be “gas,” such as compressed natural gas (CNG) or liquefied petroleum gas (LPG).
That is, the bi-fuel vehicle means a vehicle which stores two types of fuel, and the driver may obtain economic efficiency by supplying the vehicle with gas fuel that is inexpensive compared to gasoline fuel, or may obtain higher driving performance and improve vehicle performance by supplying the vehicle with gasoline fuel which exhibits better fuel efficiency compared to gas fuel.
However, in the case of the bi-fuel vehicle, at the time of charging a vehicle with liquefied petroleum gas (LPG) fuel in summer, a temperature in an LPG tank in the vehicle is increased because of an outside temperature in summer, and pressure in the LPG tank is increased accordingly, and as a result, the pressure in the LPG tank becomes higher than a charging pressure of an LPG fuel station, which may result in a problem of filling the vehicle with LPG.
The above information disclosed in this Background section is only for enhancement of understanding the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.